The number of echoes combined into a single image or image set in multiple echo imaging sequences or echo-train techniques such as rapid acquisition with relaxation enhancement (RARE), fast-spin echo (FSE), and turbo spin-echo (TSE). In RARE imaging, the ETL typically equals the acceleration factor.
As for tooth pain, it is caused by a reaction of the nerves inside a tooth's pulp chamber with the severity dependent upon the type and degree of the stimulus. What follows are some examples of symptoms you may be feeling and their possible causes.
Pain around the teeth and the jaws can be symptoms of heart disease such as angina. If your dentist suspects a medical illness could be the cause of your toothache, he or she may refer you to a physician. If you have a toothache, you may have a cavity or advanced gum disease. The first sign of decay may be the pain you feel when you eat something sweet, very cold or very hot. If the pulp â the inside of the tooth that has tissue and nerves â has become irritated, this can cause pain in your tooth.